Muzzle burst fuzes

ABSTRACT

This invention relates to a muzzle burst inertia responsive fuze for a projectile warhead which is designed to spin about its longitudinal axis. The fuze having a cylindrical housing whose longitudinal axis is parallel to the projectile longitudinal axis, a centrally located shutter cam cavity positioned in the housing immediately adjacent to an explosive train, a shutter camming means positioned in the housing so that it is slidably responsive to the projectile spin when the projectile exits from the launcher and fixedly held motionless when the projectile is in the launcher, a spin actuated detent means biasedly positioned in the housing for releasably holding the shutter camming means, and a firing pin means operatively held in the housing adjacent to the shutter camming means for engaging and holding the camming means in a stationary safe position while the projectile is in the launcher, and initiating detonation of the projectile when the camming means has aligned a stab detonation over an explosive train.

United States Patent 11 1 1111 3,738,274

Brothers 1 June 12, 1973 MUZZLE BURST FUZES sive fuze for a projectile warhead which is designed to [75] Inventor: Jack Brohers, Succasunna Ni spin about its longitudinal axis. The-fuze having a cylin drical housing whose longitudinal axis is parallel to the Assigneer The United stales America a projectile longitudinal axis, a centrally located shutter p y ""7 Secretary of the cam cavity positioned in the housing immediately adjay Washington, DC cent to an explosive train, a shutter camming means po- [22] Filed: Jam 24, 1972 sitioned in the housing so that it is slidably responsive to the projectile spin when the projectile exits from the PP Nod 219,993 launcher and fixedly held motionless when the projec- I tile is in the launcher, a spin actuated ,detent means bi- 52 US. Cl 102/70, 102/79, 102/83 asedly psitined musing releasably wing 51 Int. Cl. F42c 15/26 the shutter camming means and a firing means 58 Field of Search 102/70, 78, 79, so, eatively held in musing adjacent the shutter 102/86 82 83 camming means for engaging and holding the camming means in a stationary safe position while the projectile [56] References Cited is in the launcher, and initiating detonation of the pro- 1 jectile when the camming means has aligned a stab det- UNITED STATES PATENTS onation over an explosive train. 2,609,753 9/1952 Rosenberg 102/79 2,782,717 2/1957 Bum et a] n The invention described herein may be manufactured,

3,118,379 1964 jasse u used and licensed by or for the Government for 3,329,090 7/1967 Rhoads 102/70 R governmental P p Without the Payment to me of 1 any royalty thereon.

Primary ExaminerSamuel W. Engle Attorneyl-larry M. Saragovitz, Edward J. Kelly, Herbert Berl et al.

[57] ABSTRACT I 5 Claims, 7 Drawing Figures ThlS invention relates to a muzzle burst inertia respon- MUZZLE BURST FUZES BACKGROUND OF THE INVENTION that was slidably or rotatably held within a sleeve.

Other prior art muzzle firing devices have utilized various balls, sliding members and springs to hold a preloaded biased firing pin in a safe position and the primary detonator in an out-of-line position relative to the detonator lead train so that latter could not be actuated unless it received the setback force of a gun. The aforementioned prior art devices require, for reliable operation, close part tolerances between mating surfaces and are therefore expensive to manufacture. The-prior art devices are also not as satisfactory as the present device because of their relatively larger size, the increased size reduces the potential lethality of the projectile.

SUMMARY OF THE INVENTION The present device requires no pre-loaded spring for driving the firing pin into a detonator. In one of the embodiments of the present invention the camming action of a centrifugally driven shutter deflects the firing pin and stores energy in an integral firing pin spring cantilever member. When the projectile is in the gun barrel, the set back forces of the launch holds the firing pin in a node position away from the elevating shutter cam. The shutter is pivotally positioned and operatively held by a biased spin responsive detent so that an integrally held primary explosive, a stab detonator, is out-of-line with the secondary explosive train. When the setback forces go to zero upon exit of the projectile from the muzzle of the gun, the inertia of the shutter mass and the spin of the projectile centrifugally drives the pivoted shutter so that it firstcocks the firing pin and then subsequently releases it so that it will impact on the stab detonator. The stab detonator in turn initiates a flash detonator which is aligned with the explosive train. A second modification of the aforementioned embodiment utilizes a slider camming mechanism which is likewise responsive to the spin forces and held in the safe position by the setback forces during the launch. The slider design utilizes the same type of centrifugally cam cocked cantilever firing pin as aforedescribed.

A third embodiment of the present invention eliminates the camming action of both the pivoted shutter and the slider to bias a firing pin and substitutes therefor a fixed firing pin which is operatively positioned adjacent to a detent held, spin responsive, pivoted shutter, in one design anda slider in an alternative fourth embodiment. In both the third and fourth embodiments of the present inventionja pair of flash detonators are positioned out-of-line with an explosive train while in the safe position. The slider and pivoted shutter are constructed so that a lateral flash hole in the slider and shutter connect the two flash detonators with a stab detonator. Prior to launch, biased spin detents hold the slider and shutter embodiments in the unarmed position. When the projectile is launched the holding detent, the pivoted shutter in one embodiment, and the slider in the other embodiment, is locked against the fuze body by the setback force. As previously described in the first and second embodiments, when the projectile leaves the launcher setback decays to zero while spin remains. In the third ai'id fourth embodiments the detents are spun out of the slider by the centrifugal force. This spin associated force in the case of the slider embodiment and the inertial force in the shutter embodiment moves these elements toward the armed position. When the slider reaches the end of the armed position it slams a stab detonator against a firing pin while simultaneously aligning the flash detonators with an explosive train. The explosive output from the stab detonator flashes thru a flash hole and initiates the flash detonator which functions the explosive train.

One of the objects of this invention is to provide a muzzle burst fuze mechanism which is small in size, inexpensive to fabricate, and reliable in its operation.

Another object of this invention is to provide a muzzle burst fuze device whose firing pin is in an unbiased position and incapable of striking a detonator when the projectile is in the launcher.

Another object of this invention is to prevent in-bore malfunction by providing a muzzle burst fuze device whose explosive train is out-of-line with respect to its detonator when the projectile is in the launcher.

Another object of this invention is to provide a muzzle burst fuze device having a firing pin which is held by setback forces in an unbiased position while in a launcher and cam actuated to strike a detonator by spin forces when the projectile leaves the launcher.

While certain objects, features and advantages of the present invention have'been specifically pointed out, others will become apparent from the following description taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial isometric, cut-away cross-sectional view of one of the preferred embodiments of a muzzle burst fuze device having a pivoted shutter camming means, showing the relative position of the fuze elements when the projectile is in the launcher and the fuze is in its safe condition.

FIG. 2 is a partial isometric, cut-away cross-sectional view of the preferred embodiment illustrated in FIG. 1 showing the relative position of the fuxe elements just after the projectile has left the launcher, where setback forces have gone to zero, and the inertial and spin forces' have placed the fuze elements in an armed condition.

FIG. 3 is a partial isometric, cut-away cross-sectional view of the preferred embodiment illustrated in FIGS. 1 and 2 just after the projectile has passed from the armed condition to the fired position and the projectile is just a short distance away from the launcher.

FIG. 4 is a partial isometric, cut-away cross-sectional view of a second preferred embodiment of a muzzle burst fuze device showinga slider camming means and the relative position of the fuze elements when the projectile is in the launcher and the fuze is in its safe condition.

FIG. 5 is a partial isometric, cut-away cross-sectional view of the second preferred embodiment illustrated in FIG. 4 showing the relative position of the fuze elements just after the projectile has left the launcher, when setback forces have gone to zero and the spin forces have placed the fuze elements in an anned condition just prior to firing of the detonator.

FIG. 6 is a partial isometric, cut-away cross-sectional view of a third preferred embodiment of a muzzle burst fuze device showing a spin activated pivoted shutter detonator carrying means in its spatial relation to a fixed firing pin and explosive train, when the projectile is in the launcher and the fuze is in a safe condition.

FIG. 7 is a partial isometric, cut-away view of a fourth preferred embodiment of a muzzle burst fuze device showing a spin activated slider detonator carrying means in its spatial relation to a fixed firing pin and an explosive train, when the projectile is in the launcher and the fuze is in a safe condition.

Throughout the following description like reference numerals are used to denote like parts in the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1, 2 and 3 a fuze body 10 is attached to the forward end of a projectile shell body (not shown) so that the longitudinal axis 12 of the fuze is axially aligned with the shell body longitudinal axis. When the projectile is launched the fuze and the fuze elements are subjected to spin and setback forces. Inertial forces resulting from the sudden acceleration of the projectile forces a firing pin 14 which is part of firing pin cantilevered appendage 16 and firing pin ring. 17, into a firing pin detent hole 18 which is located in one corner of an L shaped pivoted shutter 20. Shutter 20 is located in a pie shaped cavity 21 in the fuze body 10. The force of setback, during the launch period, also forces the shutter 20, the shutter detent pin 22, the detent spring 24 against the fuze body 10, locking all of the aforementioned elements in the unarmed, safe position, as shown in FIG. 1. When the projectile emerges from the launcher (not shown), the setback forces are reduced to zero, but the centrifugal forces induced by missile spin continue. FIG. 2 shows how the centrifugal force of spin causes the detent pin 22 to withdraw from a detent shutter bore 26 which is located in shutter 20. The centrifugal and the inertial force due to spin also forces the shutter which is pivoted about shutter pivot bearing 28 to move toward the open shutter cavity 21 into an armed" position as shown by FIG. 2. As the shutter 20 moves in a clockwise direction about pivot bearing 28 toward the armed position, a shutter cam 30, which is an integral part of the shutter member 20, deflects the cantilevered appendage 16 so that firing pin 14 is removed from the firing pin detent hole 18 thereby permitting the shutter 20 to move clockwise, as previously stated, spring loading the cantilevered appendage 16. As the shutter 20 continues to move counter clockwise, a stable detonator 32, which is fixedly located in one leg of the shutter L, moves from its out-of-line position as shown in FIGS. 1 and 2 to a position in line with the explosive train 34.

FIG. 3 shows the shutter camming means 20 in its furthermost clockwise direction which constitutes the fire" position. In the fire position the shutter cam 30 no longer supports the biased cantilever appendage 16 thereby permitting it to move rapidly toward its node position. This movement toward the node position drives the firing pin 14 into the stab detonator 32, firing the stab detonator 32 and causing the detonator in turn to ignite the explosive train 34, which is now in line with the stab detonator 32, thereby exploding the projectile just outside of the launcher muzzle.

FIG. 4 shows the safe" position for a second embodiment of the muzzle burst fuze previously described in FIGS. 1, 2 and 3. A firing pin ring 17 has an integral radial cantilevered appendage 36 which has on its free end a firing pin 14 and appendage firing pin camming surfaces 38 and 41. A partially cylindrical slider 40 is slidably positioned in a cylindrical fuze bore 42 whose longitudinal axis is perpendicular to the longitudinal axis 12 of the fuze body 10. In the armed position a biased spin detent 22 is slidably held by detent spring 24 so that detent shaft 44 fits into a slider detent bore 46. A detent plug 48 maintains the detent spring 24 compressive force against the detent 22. A parallel pair of slider camming grooves 50 and 52 are longitudinally and peripherally located parallel to the slider longitudinal axis 54. Firing pin camming surfaces 38 and 40 slidably engage the slider camming grooves 50 and 52 thereby preventing slider 40 from inadvertently rotating about the slider longitudinal axis 54. Similarly, as described in the embodiment shown in FIG. 1, setback forces hold firing pin 14 in firing pin slider detent hole 56 while the projectile is in the launcher. In the armed position the slider 40 holds a stab detonator 32, located therein, out of alignment with the explosive train 34. When the projectile leaves the launcher and the setback forces are reduced to near zero the centrifugal forces due to the spin of the projectile cause the detent shaft 44 to move out of the slider detent hole 46 as shown in FIG. 5. The centrifugal force also causes the slider 40 to move radially away from the fuze body 1ongitudinal axis 12 deflecting the firing pin camming surfaces 38 and 41 by the slider cams 58 and 59 (not shown). When the slider 40 aligns the stab detonator 32 with the explosive train 34, camming action is removed suddenly, allowing the deflected cantilever appendage 36 to spring back towards its node position thereby allowing the firing pin 14 to forcibly penetrate into the stab detonator 32 functioning the aligned explosive train 34.

Referring to the third embodiment shown in FIG. 6 a fuze body 10 contains a pivoted L shaped shutter 60 in a pie shaped shutter cavity 21. The shutter 60 in this particular embodiment holds a pair of flash detonators 62 and 62' spatially separated from a stab detonator 32 and interconnected thereto by a flash hole 64, a shutter detent hole 26, and a shutter pivot bearing 28. When the projectile is launched the force of setback locks the shutter 60 and the spin actuated detent 22 in the safe position. When the setback force is reduced to zero as the projectile emerges from the launcher (not shown) the centrifugal force caused by the projectile spin remains, this latter force removes the detent 22 from the shutter detent hole 26 and forces the shutter to rotate in a clockwise direction about the shutter pivot bearing 28. The shutter 60 moves rapidly to the armed position driving the stab detonator 32 against the stationary firing pin 66 functioning the stab detonator 32. The output from the stab detonator 32 flashes thru the flash hole 64 igniting both flash detonators 62 and 62 which, in the armed position, are aligned with the explosive train 34 and which in turn ignite the explosive train causing the projectile to explode just outside of the muzzle.

Referring to the fourth embodiment shown in FIG. 7 a fuze body 10 has a cylindrical shaped slider 68 slidably positioned in a radial cylindrical slider cavity 70 whose longitudinal axis 72 is perpendicular to the fuze body longitudinal axis 12 which is axially aligned with the longitudinal axis of the projectile (not shown). The slider 68 contains two flash detonators 62 and 62' which are held out of alignment with an explosive train 34 while the projectile is in the launcher. The detonators 62 and 62' are spatially separated from a stab detonator 32 and interconnected thereto by a flash hole 74. The slider 68 also contains two oppositely positioned slider detent holes 76 and 76' which slidably retain therein two spring loaded spin actuated detents 78 and 78'. A stationary firing pin 80 is axially staked with the slider longitudinal axis in one end of the slider cavity 70. Until the projectile is launched, the detents 78 and 78 keep the slider 68 in the unarmed position as illustrated. Initially, when the projectile is launched, the 15 flash detonators 68 and 68 with the explosive train 34.

The explosive output from the stab detonators 32 flashes thru the flash hole 74 and initiates the flash detonators 62 and 62 which in turn cause the explosive train 34 to function.

From the above description it will be evident that the invention provides in the preferred embodiments a muzzle burst fuze which will not malfunction while in the launching device; is reliable in its operation because of the simplicity and ruggedness of the fuze elements; is relatively inexpensive to manufacture because of the small number of parts; and is small in size having a volume of approximately 1.0 cubic inch.

I wish it to be understood that I do not desire to be limited to the exact detail of construction shown and described for obvious modification will occur to a person skilled in the art.

What is claimed is:

l. A motion responsive fuze for detonating a projectile warhead which spins about a projectile longitudinal axis and explodes external to a launcher muzzle which comprises:

. a housing having a housing longitudinal axis and a centrally located shutter cam cavity operatively positioned therein;

' a shutter-camming means, operatively positioned in said housing shutter cam cavity so that said camming means is slidably responsive to said projectile spin in a plane perpendicular to said housing longitudinal axis;

spin actuated detent means biasedly positioned in said housing for releasably holding said shuttercamming means stationary when said projectile is fired and traveling within said launcher, releasing said shutter-camming means when said projectile exits from said launcher muzzle;

an explosive train disposed proximate said cam cavity; and

a firing pin means operativley held in said housing adjacent to said shutter-camming means for engaging and holding said camming'means in a stationary safe position while said 'projectile is in said launcher and initiating detonation of said projectile when said camming means is aligned over said explosive train.

2. A muzzle burst fuze as recited in claim 1 wherein said camming means comprises:

an L" shaped shutter member having a cylindrical shutter pivot bearing on one end of leg of said L member, a cylindrical stab detonator operatively positioned in the other leg of said L member so that it is directly over said explosive train when said shutter is in an armed position;

said shutter member having a firing pin detent bore positioned at the intersection of said L member legs;

an integral cam projecting surface intermediate to said stab detonator and said firing pin detent bore, said firing pin detent bore operatively engaging and holding unbiased said firing pin means and locking said shutter in a safe position when said projectile is within said launcher; and

said shutter having a cylindrical shutter detent bore having a longitudinal axis aligned with said spin actuated detent means, and for holding therein said spin detent means.

3. A muzzle burst fuze as recited in claim 1 wherein said camming means comprises:

a partially cylindrical shutter radially positioned in said shutter cam cavity so that said cylindrical shutter longitudinal axis is perpendicular to said housing longitudinal axis, a cylindrical stab detonator operatively positioned in said shutter so that said detonator is directly over said explosive train when said fuze is in an armed position and is out-of-line therewith when said fuze is in a safe position, said shutter having therein a firing pin means detent hole located adjacent to said detonator for opera tively engaging and holding said firing pin means and locking said shutter in a safe position, a parallel pair of camming grooves peripherally located parallel to said shutter longitudinal axis for preventing said shutter from rotating about its longitudinal axis, a shutter cam surface intermediately located within said parallel grooves slidably biases said firing pin means so that said firing pin means forcibly impacts upon said stab detonator when said shutter moves radially away from said fuze longitudinal axis, said shutter slider having a cylindrical shutter detent bore whose longitudinal axis is aligned with said spin actuated detent means for holding said shutter stationary while said fuze is in a safe position.

4. A muzzle burst fuze as recited in claim 1 wherein said spin actuated detent means comprises:

a detent shaft radially positioned in said housing having a longitudinal axis perpendicular to the longitudinal axis of said fuze and axially aligned with said cylindrical shutter detent bore and slidably fitting therein for holding said shutter locked in a stationary position when said projectile is in said launcher;

a spring urging said detent shaft toward said shutter means.

5. A muzzle burst fuze as recited in claim 1 wherein said firing pin means comprises:

a flat ring having a radial cantilevered appendage integrally attached to the inner circumferential edge of said ring, a firing pin integrally formed from said appendage is operatively positioned to fit into said shutter firing pin detent hole and impact upon said 

1. A motion responsive fuze for detonating a projectile warhead which spins about a projectile longitudinal axis and explodes external to a launcher muzzle which comprises: a housing having a housing longitudinal axis and a centrally located shutter cam cavity operatively positioned therein; a shutter-camming means, operatively positioned in said housing shutter cam cavity so that said camming means is slidably responsive to said projectile spin in a plane perpendicular to said housing longitudinal axis; spin actuated detent means biasedly positioned in said housing for releasably holding said shutter-camming means stationary when said projectile is fired and traveling within said launcher, releasing said shutter-camming means when said projectile exits from said launcher muzzle; an explosive train disposed proximate said cam cavity; and a firing pin means operativley held in said housing adjacent to said shutter-camming means for engaging and holding said camming means in a stationary safe position while said projectile is in said launcher and initiating detonation of said projectile when said camming means is aligned over said explosive train.
 2. A muzzle burst fuze as recited in claim 1 wherein said camming means comprises: an ''''L'''' shaped shutter member having a cylindrical shutter pivot bearing on one end of leg of said ''''L'''' member, a cylindrical stab detonator operatively positioned in the other leg of said ''''L'''' member so that it is directly over said explosive train when said shutter is in an armed position; said shutter member having a firing pin detent bore positioned at the intersection of said ''''L'''' member legs; an integral cam projecting surface intermediate to said stab detonator and said firing pin detent bore, said firing pin detent bore operatively engaging and holding unbiased said firing pin means and locking said shutter in a safe position when said projectile is within said launcher; and said shutter having a cylindrical shutter detent bore having a longitudinal axis aligned with said spin actuated detent means, and for holding therein said spin detent means.
 3. A muzzle burst fuze as recited in claim 1 wherein said camming means Comprises: a partially cylindrical shutter radially positioned in said shutter cam cavity so that said cylindrical shutter longitudinal axis is perpendicular to said housing longitudinal axis, a cylindrical stab detonator operatively positioned in said shutter so that said detonator is directly over said explosive train when said fuze is in an armed position and is out-of-line therewith when said fuze is in a safe position, said shutter having therein a firing pin means detent hole located adjacent to said detonator for operatively engaging and holding said firing pin means and locking said shutter in a safe position, a parallel pair of camming grooves peripherally located parallel to said shutter longitudinal axis for preventing said shutter from rotating about its longitudinal axis, a shutter cam surface intermediately located within said parallel grooves slidably biases said firing pin means so that said firing pin means forcibly impacts upon said stab detonator when said shutter moves radially away from said fuze longitudinal axis, said shutter slider having a cylindrical shutter detent bore whose longitudinal axis is aligned with said spin actuated detent means for holding said shutter stationary while said fuze is in a safe position.
 4. A muzzle burst fuze as recited in claim 1 wherein said spin actuated detent means comprises: a detent shaft radially positioned in said housing having a longitudinal axis perpendicular to the longitudinal axis of said fuze and axially aligned with said cylindrical shutter detent bore and slidably fitting therein for holding said shutter locked in a stationary position when said projectile is in said launcher; a spring urging said detent shaft toward said shutter means.
 5. A muzzle burst fuze as recited in claim 1 wherein said firing pin means comprises: a flat ring having a radial cantilevered appendage integrally attached to the inner circumferential edge of said ring, a firing pin integrally formed from said appendage is operatively positioned to fit into said shutter firing pin detent hole and impact upon said stab detonator. 